BUNSEKI KAGAKU
Print ISSN : 0525-1931
Volume 43, Issue 1
Displaying 1-16 of 16 articles from this issue
  • An approach using ion-transfer voltammetry
    Toshiyuki OSAKAI, Sadayuki HIMENO, Atsuyoshi SAITO
    1994 Volume 43 Issue 1 Pages 1-15
    Published: January 05, 1994
    Released on J-STAGE: January 15, 2010
    JOURNAL FREE ACCESS
    Heteropolyanions are widely used as acid and redox catalysts for various synthetic reactions. Also, their formation reactions have been the basis of the widely utilized methods for the determination of such oxoanions as phosphate and silicate ions. In such analytical processes, either water-immiscible or water-miscible organic solvents have been used very effectively as extraction solvents and auxiliary solvents for stabilizing heteropoly complexes. Although many heteropolyanions possess hydrophobic characterisctics, there has been no available measure for evaluating the affinity of heteropolyanions to organic solvents. Over the past several years, we employed ion transfer voltammetry to study the transfer of heteropoly- and isopolyanions at the oil/water interfaces, viz., nitrobenzene/water and 1, 2-dichloroethane/water interfaces. The standard ion transfer potentials(ΔWOφ_??_)of the polyanions tested were found to depend linearly on the quantity |z|/n2/3 (z, ionic valence, n, number of oxygen atoms), which can be regarded as being proportional to the surface charge density of a spherical polyanion. On the basis of this result, we proposed the value |z|/n2/3 to be used for a hydrophobicity scale of polyanions. This scale may provide a useful criterion for evaluating the hydrophobic (or hydrophilic) properties of polyanions, including the stability in solutions and extractability into organic solvents. The linear dependence of ΔWOφ_??_ on the surface charge density provides significant information regarding ion solvation energy as well. This dependence means that the Gibbs transfer energy depends linearly on 1/γ2 (γ, ionic radius), and it cannot be accounted for by the Born-type electrostatic solvation energy, which should depend on 1/γ. Such a non-Bornian solvation energy may be considered as the short-range interactions of an ion with solvent molecules (i.e., donor-acceptor effects or hydrogen bonds), which seem to play the most important role in the ion transfer energy. In addition to the contribution to solution chemistry, a few contributions have been made to coordination chemistry and electroanalytical chemistry, i.e., the characterization of aqueous polyanion solutions and the development of a novel voltammetric phosphate sensor.
    Download PDF (2387K)
  • Junko MOTONAKA, Hiroyuki KIYOKU, Shinji OKADA, Sanae IKEDA, Nobuyuki T ...
    1994 Volume 43 Issue 1 Pages 17-23
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A rapid method was proposed for the determination of myoglobin by the potentiometric argentimetric titration of iodide ions, liberated in proportion to the amount of myoglobin at constant condition when myoglobin was treated with an iodine-ethanol solution using an iodide-selective electrode. The reaction ratios of standard amino acids to iodine, stability of the myoglobin, effect of the amounts of iodine, effect of ethanol, effect of temperature, effect of added sulfuric acid, effect of the reaction time, effect of concomitant compounds and precision data of myoglobin are discussed. The recommended procedure was as follows. A sample containing 0.14414.4 mg myoglobin was taken into a 50 ml-titration cell and treated with 5 ml of a 5 mM iodine-ethanol solution. In addition, 3 ml of 1 M sulfuric acid was introduced into the sample solution. The volume was adjusted with distilled water to 50 ml which was then titrated potentiometrically with a 330 mM standard silver nitrate solution. These procedures were performed at room temperature (25°C). Upon the addition of sulfuric acid, the potential jump of the titration curve was enhanced. Myoglobin (0.14414.4 mg) was determined with an RSD less than 3.8% at room temperature (25°C). The calibration curve was drawn using the equation Y=0.235X+0.0009, Y being the added silver nitrate weight in mg and X the myoglobin weight in mg. The coefficient of correlation was 0.999.
    Download PDF (800K)
  • Toshihiro SHIRASAKI, Keizo HIRAKI
    1994 Volume 43 Issue 1 Pages 25-29
    Published: January 05, 1994
    Released on J-STAGE: January 15, 2010
    JOURNAL FREE ACCESS
    The optimum conditions for the direct analysis of Cr, Mn, Fe, Ni, Cu and Pb in photresist by microwave-induced plasma mass spectrometry (MIP-MS) have been investigated. Nitrogen gas, an air and an oxygen-nitrogen mixed gas (oxygen gas in a carrier gas) could be sustained for the plasma souce of MIP-MS. However, nitrogen and an air plasma were not appropriate for analyzing trace elements in organic solutions. The nitrogen plasma was not sufficient for resolving organic solvents. Although an air plasma was sufficient for resolving organic solvents, an Ar ion peak appeared as well as its associated compound. Then, an oxygen-nitrogen plasma was used for analyzing trace metals in a photoresist solution. We carried out an examination of the microwave power on the metal ion intensity and MO-/M- ratio. The proposed method was applied to the determination of Cr, Mn, Fe, Ni, Cu and Pb in commercial photoresist solutions. The photoresist solutions were diluted 10 times with 2-ethoxyethly acetate. These samples were introduced to MIP-MS directly, and were analyzed. The analytical results were in good agreement with the values obtained by graphite-furnace AAS. The detection limits (3σ) were 0.01μg/l for Cr, 0.01μg/l for Mn, 0.05μg/l for Fe, 0.06μg/l for Ni, 0.10μg/l for Cu and 0.04 μg/l for Pb.
    Download PDF (779K)
  • Hiroki OHURA, Toshihiko IMATO, Sumio YAMASAKI, Nobuhiko ISHIBASHI
    1994 Volume 43 Issue 1 Pages 31-37
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A sensitive and rapid potentiometric FIA method for the determination of Cr(VI) in seawater is proposed, using both a redox potential electrode and an Fe(III)-Fe(II) potential buffer containing bromide. The method is based on the detection of a large transient potential change due to bromine generated by an oxidation reaction between bromide and Cr(VI) in the presence of Fe(II). The oxidation reaction was estimated to be induced by Fe(II) from spectrophotometric studies. A sensitive determination of Cr(VI) was achieved by detecting the sharp transient potential change within 10 s after mixing the Cr(VI) sample with the potential buffer by using an appropriately designed FIA system. Analytical sensitivity obtained by the proposed method is enhanced to about 70 times that of on FIA system using a potential buffer without bromide. A detection limit of 2×10 -8 M Cr(VI) was achieved by using a 1×10 -4 M Fe(III)-Fe(II) potential buffer containing 0.4 M NaBr and 1.2 M H2SO4. The R.S.D. was 0.6% (n=6) for the determination of 1×10 -6 M Cr(VI) with the sampling rate of about 40 h -1. Several heavy metal ions such as Cr(III), Cu(II), Zn(II), Ni(II) and Cd(II) did not interfere with the determination of Cr(VI) even in the case where their concentration was more than 103 times that of Cr(VI). The proposed method was applied to the determination of Cr(VI) in real seawater sample, and was found to provide a good recovery for seawater samples containing Cr(VI) at the 500 ppb level, a concentration of effluent common in Japan.
    Download PDF (1156K)
  • Qiangbin ZHANG, Hirotsugu MINAMI, Ikuo ATSUYA
    1994 Volume 43 Issue 1 Pages 39-43
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A new method for the direct determination of lead at the 10 ppb level in powdered biological samples by Zeeman-AAS with solid sampling technique using a miniature cup has been established. In this case, the concentration of lead in powdered biological samples is lower than that of the detection limit of Z-AAS, therefore these biological samples must be concentrated by a pre-ashing method with a conventional electrothermal Muffle furnace. The standard addition method for solid sampling technique (3 point estimation method) is proposed for the direct determination of lead at the 10 ppb level. Heating conditions of 500°C, 30 min for the pre-ashing concentration method are recommended.It has been ascertained that lead is not volatilized under these conditions, and it has been found that accurate analytical results for the direct determination of lead at the 10 ppb level in powdered biological standard samples, such as those issued by NIES, NIST etc. are obtained.
    Download PDF (817K)
  • Nobuhiro YAMAMOTO, Masashi NISHIDA, Isao YOSHIDA, Fumio SAGARA, Keihei ...
    1994 Volume 43 Issue 1 Pages 45-50
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    Complex formation of manganese(II) with tetrasodium 25, 26, 27, 28-tetrahydroxycalix[4]arene-5, 11, 17, 23-tetrasulfonate (CALX-S4) and its application to the spectrophotometric determination of manganese(II) in solution were studied. Manganese(II)reacted with CALX-S4 to form a 1 : 1 red-purple complex in aqueous alkaline solution. The color intensity increased with the increase in pH, approaching a maximum at pH 10.4pH 11.3. The absorption peak appeared at 495 nm, and the molar absorption coefficient was 9.19×103 M-1 cm -1at the peak. This color reaction was highly selective for manganese(II); except for manganese(II), only cerium(III) formed a colored complex with CALX-S4 under the conditions recommended for the determination of manganese(II). Chromium(III) caused negative errors, and a large amount of iron(III) also interfered by forming a colored species. Interferences due to the presence of those ions could be eliminated by removing them as their thiocyanate complexes using a column packed with an anion exchange resin. The proposed (CALX-S4) method was applied successfully to the determination of manganese(II) in an artifical sample solution and in the sludge formed in a tube which was used to pump up ground water.
    Download PDF (1005K)
  • Hiromu IMAI, Masayuki HASHIMOTO, Yasuo NAKABAYASHI
    1994 Volume 43 Issue 1 Pages 51-56
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    The nitrobluetetrazolium (NBT) method was improved for the spectrophotometric determination of the superoxide ion (O2- ). The proposed method is carried out as follows; pour 0.3 ml of a DMSO solution containing O2- (concentration, <2×10-1 mM) into a 30 ml test tube, in which 0.1 ml of O2--free DMSO was previously added, add 4.6 ml of a 2 mM NBT aqueous solution adjusted to pH 7.4, and finally add 1 ml of a 10 mM MgSO4 aqueous solution to this solution. The solution contains the precipitate of blueformazan formed; the precipitate aggregates by shaking for 45 min at 40°C. Filter the precipitate with a cellulose nitrate membrane filter (pore size of 0.45 μm), and dry it with suction ; dissolve firstly the membrane filter in 2 ml of DMSO, and further dissolve the blueformazan by addition of 8 ml hexamethylphosphoramide; measure the absorbance of this solution at a wavelength of 572 nm. The calibration curve of O2- was linear in the range of 0.2×10-1 to 2.0×10-1 mM. This procedure can be applied to the research of scavengers for O2-.
    Download PDF (811K)
  • Masae MIYAKAWA
    1994 Volume 43 Issue 1 Pages 57-60
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    In FT-IR microreflection spectroscopy, interference spectra often obstruct the analysis of the sample spectra. The interference spectra occur when the following conditions are satisfied: 1) the difference between the refractive index of a sample layer and that of its substrate is large; 2) the surface of the film and the substrate are optically smooth; 3) the thickness of the film is about 0.3100 μm. One may prevent the occurrence of the interference spectra by avoiding the above conditions. Unfortunately the first and second conditions cannot be changed because the refractive indices are constant, and it is difficult to process the sample surface when the substrate is hard and its area is very small. The third condition can be prevented by putting a transparent material, which has almost the same refractive index, on the sample to increase the film thickness. However, when we put a thin KBr crystal on the sample, another interference spectra occured due to the air gap between the KBr crystal and the sample surface. This problem was solved by filling this gap with liquid paraffin. By applying this method to the measurement of a photoresist resin layer on a silicon substrate, a good result was obtained.
    Download PDF (660K)
  • Kunihiko AKATSUKA, Suwaru HOSHI, J.W MCLAREN, S.S BERMAN
    1994 Volume 43 Issue 1 Pages 61-66
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A reliable procedure has been developed to separate nanogram platinum from hafnium, iron, alkali and alkaline-earth elements in dust samples for inductively coupled plasma mass spectrometry. The proposed procedure involves ashing at 700°C, decomposition in acid, separation and preconcentration of the analyte by anion exchangers. A rapid dissolution of the dust material was achieved by digestion in pressured vessels in a microwave oven, and subsequent evaporation on a hot-plate. The anionic form of platinum is adsorbed onto an anion-exchange column under acidic conditions in the 0.53 M HCl range. The interfering matrix ions and hafnium are not complexed, but pass through the column unretained. The platinum complex is then removed from the column with 40 ml of HNO3 at 90°C. The recovery was more than 60% for 10 ng of Pt, and the obtained column blank was 2.8±0.2 ng Pt. A stable isotope dilution method has been employed for the determination. The detection limit of the method, based on 1 g of dust sample, was 1.4 ng g-1 for Pt.
    Download PDF (1000K)
  • Ken-ichi AKIYAMA, Shin-ichiro KAWABATA, Kazuhiko SAKAMOTO
    1994 Volume 43 Issue 1 Pages 67-69
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    In order to grasp the emission characteristics of automotive exhaust gas, high sensitivity and continuously measuring method is required. In this investigation, a continuous measuring technique for determining methanol in automotive exhaust gas with high resolution mass spectrometer was developed. Methanol in the automotive exhaust gas was measured every 1 second by a high resolution mass spectrometry at m/z=32.026. The exhaust gas was directly introduced to injected mass spectrometer. Detection limit of methanol with this method was 0.1 ppm (S/N=2), and 100% response time was 2 s.
    Download PDF (406K)
  • Mikiya OHTO, Atsushi YAMAMOTO, Akinobu MATSUNAGA, Eiichi MIZUKAMI
    1994 Volume 43 Issue 1 Pages 71-74
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    According to the official method, the 4 pesticides used on golf courses (mecoprop, oxin-copper, simazine, and thiram) which leach into the drinking water supply are to be determined separately. A simple and simultaneous method of determination of these pesticides is described in this paper. Two milliliters of filtered sample was injected into the on-line enrichment column which was a substitute for an injection loop of a sample injector. Back-flushed pesticides, using a pumped mobile phase onto an analytical column, were analyzed. Conditions for HPLC analysis were as follows: analytical column, Shodex RSpak DE-613; extraction column, Merck LiChroCART; mobile phase, 50% aqueous solution of acetonitrile containing 0.5 mM phosphoric acid. Linear calibration curves based on the peak area were obtained in a range of 120 ng, 0.6100 ng, 0.420 ng, and 120 ng for mecoprop, oxin-copper, simazine, and thiram, respectively. Detection limits (S/N=5) were 0.6 ng, 0.2 ng, 0.1 ng, and 0.4 ng for mecoprop, oxin-copper, simazine, and thiram, respectively. The recoveries of the 4 pesticides added to drinking water at the 5 or 10 μg/l level ranged from 93 to 101 %. The proposed method is considered to be applicable for the routine examination of water.
    Download PDF (526K)
  • Eiko NAKAMURA, Hiroshi OMOKAWA, Hiroshi NAMIKI
    1994 Volume 43 Issue 1 Pages 75-79
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    In non-suppressed ion chromatography with conductivity detection, a suspension of H-form cation exchange resin (SCR) was added to the eluate from the ion separating column. Sodium ions in the eluate were replaced by hydrogen ions, so that the background conductivity was reduced and anions were detected with higher sensitivity. The SCR was prepared as follows. A cation exchange resin (Amberlite IR-120B), converted into the H-form with hydrochloric acid, was ground with a millstone, and sieved to obtain the fraction which passes a 250 mesh screen. The powdered resin was suspended in water and left to stand for 2 h. The upper portion of the suspension was placed in a centrifuge tube and washed with water by centrifugation until the solution became neutral. An adequate amount of the collected fine resin was suspended in water at 0.20.5% concentration (6.315×10-3 meq/ml in ion exchange capacity). When the sodium hydrogen carbonate (1.7mM)-sodium carbonate (1.8 mM) solution was used as eluent at 0.8 ml/min and the SCR (8.2×10-3 meq/ml in ion exchange capacity) was added to the eluate at 0.8 ml/min, the background conductivity, originally 520 μS, was reduced to 15μS and 0.05 μg/ml of Cl-, 0.2 μg/ml of F-, NO2-, Br-, NO3-, PO43-and SO42-were able to be determined.
    Download PDF (648K)
  • Kazuo SAMEJIMA, Yoshio KOBAYASHI
    1994 Volume 43 Issue 1 Pages 81-84
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A determination method for methane (CH4) and its deuteride (CD4) using high-resolution mass spectrometry was developed to study methane generation from burned ash. Since the molecular ion CH4·+ (m/z 16.0313) could be distinguished from the fragment ion CD2+ (m/z 16.0282) by using a mass spectrometer having a resolution up to 12000, CH4 and CD4 could both be determined by the proposed method. This method was successfully applied to the determination of a small amount of CH4 in CD4 generated from fly ash which was treated with a D2O solution containing NaOD as a model experiment.
    Download PDF (622K)
  • Yoshikazu NAKAMOTO, Toshio TOMIYAMA
    1994 Volume 43 Issue 1 Pages 85-88
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    Organic and inorganic arsenic compounds in thermally cracked gasoline are known as catalyst poisons in the aromatization process. It is, therefore, important to determine trace arsenic in cracked gasoline. An oxy-combustion method was investigated to decompose the gasoline. During the decomposition, organic arsenic compounds were converted completely to inorganic arsenic species. After absorbing the inorganic arsenic in hydrochloric acid-iodate-iodide solution, arsenic was reduced to arsine with sodium tetrahydrogenborate and then the arsine was introduced into a quartz cell heated by an airacetylene flame. The peak height of the arsenic atomic absorption signal was measured. Several conditions; acidity in the reduction process, amount of sodium tetrahydroborate, and reaction time for arsine generation were optimized. The detection limit of the proposed method was 5 ng g-1. This method was applied to the determination of arsenic content in individual fractions from a fractionater in the aromatic hydrocarbon process.
    Download PDF (631K)
  • Yoshimi HASHIMOTO, Akira OKADA
    1994 Volume 43 Issue 1 Pages 89-92
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A method for determining trace amounts of ammonium and alkali metal ions by ion chromatography was examined. Tetramethyl ammonium hydroxide solution (40 mM) was used as the regenerant at a flow rate of 10 ml/min, which gave a lower background intensity. For optimum peak separation and sensitivity, a solution containing 25 mM hydrochloric acid and 0.25 mM 2, 3-diaminopropionic acid monohydrochloride was employed as the eluent at a flow rate of 1.0 ml/min. The detection limit (with the RSD) by this method was NH4: 10 ppb (0.67%), Li : 2 ppb (0.96%), Na : 5 ppb (0.99%), and K: 10 ppb (0.54%). It was found out that this analytic method was high in sensitivity and accuracy and could be applied to the determination of trace ammonium and alkali metal ions in a VLSI clean room.
    Download PDF (595K)
  • Masaaki HARADA, Kazuharu SUGAWARA
    1994 Volume 43 Issue 1 Pages 93-96
    Published: January 05, 1994
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    Download PDF (761K)
feedback
Top